The present invention relates to improvements in plastic reclosable fasteners or zippers with sliders for opening and closing the zippers on plastic bags and the like and particularly to the provision of plastic end clips at the ends of the plastic zipper to seal the ends of the zipper and to provide stops to retain the slider on the zipper.
Plastic reclosable fasteners or zippers with sliders are well known in the art. The plastic zippers have profiles and include a pair of male and female fastener elements in the form of reclosable interlocking rib and groove profile elements for cooperation with a slider for opening and closing the rib and groove elements. In the manufacture of thermoplastic film bags, a pair of these male and female plastic profile elements extend along the mouth of the bags and these male and female elements are adapted to be secured in any suitable manner to the flexible walls of the thermoplastic film bags. These profile elements may be integral marginal portions of such walls or they may be extruded separately and thereafter attached by a fin to the walls along the mouth of the bag. Various arrangements have been utilized heretofore to prevent the slider from sliding off the ends of the zipper. In one of the more conventional arrangements the slider included a separator finger that extends down between the integral locking rib and groove elements as the slider is moved from one edge of the bag to the other edge of the bag. When the bag is opened, the only thing to stop the slider was the side seam at the edge of the bag when the slider finger comes into contact with it. This prior art is described in U.S. Pat. No. 3,790,992--Herz. In that patent there is disclosed an arrangement wherein the heat seals that join the rib and groove elements are wider at one edge than the second edge of the bag and the wider seal is of a width at least equal to the length of the slider from its closing end of the finger so that the slider will remain fully on the bag at the end of its travel when opening the bag. The patent points out that these seal areas provide stops for the slider. Another arrangement for providing stops at the end of the zipper is disclosed in U.S. Pat. No. 3,259,951--Zimmerman. In that patent the opposite ends of the interlocking or mating strips are permanently joined or sealed to each other at the ends with the stop members sealed between the opposite ends of these members to stop the longitudinal movement of the slider therealong. U.S. Pat. Nos. 5,088,971--Herrington and 5,131,121--Herrington et al disclose end stops at the opposite ends of the reclosable fastener where the end stops are formed from the material at the opposite ends of the reclosable fastener and protrude transversely from the fastener a distance adequate to engage the slider and prevent movement of the slider passed the respective ends of the bag. With this arrangement the size of the end stops is limited by the amount of material in the ends of the fastener. Another prior art arrangement is shown in U.S. Pat. No. 5,161,286--Herrington et al. In this patent the end clamp members are located at the opposite ends of the reclosable fastener and the end clamp members are connected together by a flexible strap which extends over the top of the zipper and the rivet extends through the clamp members and the sidewalls of the bag beneath the profile elements of the zipper to secure the clamp members to the bag.
It would be desirable to provide the plastic bags wherein the zipper is terminated by end clips and the zipper and end clips fused into a single mass which creates a stronger seal because it is not limited to the cross sectional area of the profile elements and does not rely on a rivet for the strength of the seal.
The present invention provides a strong and leakproof joint and is an improvement on the end stops for plastic reclosable fastener disclosed in U.S. Pat. Nos. 5,088,591, 5,131,121 and in 5,161,286 of F. J. Herrington and Eric A. St. Phillips which disclosure is incorporated herein by this reference thereto.